Variable pitch propeller



E. B. MOORE VARIABLE PITCH PROPELLER Aug. 30, 1932.

Filed Sept. 13, 1929 4 Sheets-Sheet l INVENTOR Aug. 30, 1932.

E. B. MOORE VARIABLE PITCH PROPELLER Filed Sept. 13, 1929 4 Sheets-Sheet2 QUHL Q & 8 sl VA k R Q 1 8Q* m .N as aw 3 Q R NN 3 w v i R R R N V H QINVENTOR A'rfoRNEY Aug. 30, 1932.

E. B. MOORE 1,874,332

VARIABLE PITCH PROPELLER Filed Sept. 13, 1929 4 Sheets-Sheet 3 Aug. 30,1932. E. B M RE 1,874,332

VARIABLE PITCH PROPELLER Filed Sept. 13, 1929 4 Sheets-Sheet 4 FIGJS.

INVENTOR ATTORNEY Patented Aug. 30, 1932 UNITED STATES PATENT OFFIC EEDMUND 3.1100315, 01 HEM2STELD, NEW YORK, ASSIGNOR 'I'O AEROPLANE &MOTOR COMPANY, INC., A. CORPORATION OF NEW YORK VARIABLE PITCH PROPELLEBApplication filed sentemberla, 1929. Serial No. 892,880.

My invention relates to propellers for aeroplanes and more particularlyto methods of and means for varying thepitch of such propellers. I g

It is sometimes most advantageous to use a propeller having its bladesinclined at one A further object is to provide such means which may becontrolled b the operator of the aeroplane from the coc pit thereof.

A further object is to design the most sim ple device of such a natureand to avoid complications so that the device 'will be less like- 7 1yto get out of order. v

A further object is to provide maximum ease of operation in such adevice and to avoid danger of breakage of parts of the connectingmechanism.

Further objects are: the elimination, in

such a device, of cams and mechanically or electrically operatedclutches; the elimination therein of reversing gears; and theelimination therein of electric batteries, motors, and other heavyelectrical equipment.

Further objects will be apparent from a reading of the subjoinedspecification and claims and from a consideration of the drawings. i

In order to explain the invention more clearly, one embodimentthere'ofis shown in the accompanying drawings, in which:

Fig. 2 is a similar view in side elevation of the aeroplane of Fig. 1; i

Fig. 3 is a plan view on a, larger scale of part of the apparatus shownin Figs. 1 and 2, the ropeller blade being shown in horizontal section,the view being taken substantially on the line IIIIII of Fig. 4;

Fig. 4 is a rear elevation of the mechanism shown in Fig. 3 with partsbroken away and with parts in section, the view being takensubstantially on the line IV IV of Fig. 3 but with the propeller turnedthrough 90 degrees from its position in Fig. 3;

Fig. 5 is a vertical section of (part of the mechanism shown in Figs. 3,4 an 6 with the propeller in the position of Fig. 4 and the view beintaken substantially on the line VV of ig. 6;

Fig. .6 is a side elevation of the mechanism shown in Figs. 3, 4 and 5with the propeller in the position of Fig. 3;

Fig. 7 is a vertical section of a clutch used in one form of deviceembodying my mvention 1 8 is a vertical section of a cushion springdevice used in one form of device embodying my invention, the view beintaken ipbstantially on the line VIII I of ig. 9 is a vertical section ofthe mechanism shown in Fig. 8, the view bein taken substantially ontheline IXIX 0 Fig. 8;

Fig. 10 is an elevation of a control level used in one embodiment of myinvention;

Fig. 11 is a vertical section of a detail of a control shaftdistribution device;

Fig. 12 is a vertical section of mechanism used in one form of myinvention for projecting and retracting a pair of friction rings, theview being taken substantially on the line XIL-XII of Fig.13;

Fig. 13 is a horizontal section of the ap aratus shown in Fig. 12, theview beingta en substantially on the line XIII-XIII of Fig. 12;

Fig. 14 is a view similar to Fig. 6 with further parts broken awayandshowing a modification of the apparatus disclosed in Fi 6, saidmodification being also constructe in accordance with my invention; and

Fig. 15 is an enlarged sectional view of part of the apparatus shown inFig. 14, being somewhat similar to the sectional view shown in Fig. 12.

In general, the first form of apparatus used for illustration of myinvention comprises an aeroplane having a tractor propeller, a motor fordriving the propeller and means for varying the pitch of the propeller.This means for varying the pitch includes a pair of rolls of whicheither one may be used separatel as a driving means for two trains ofgears. he rolls and gears are mounted to rotate with the propeller andtwo of the gears mesh with two toothed sectors, one sector beingfastened to each of the propeller blades and the two sectors beingdirectly operative to vary the pitch of the propeller. A pair offriction rings are arranged to bear at times separately upon one or theother of the rolls and thus to drive the trains of gears. A controlhandle is located within the cockpit of the aeroplane and may beoperated to retract one and project the other of the rings to cause thepro ected ring to contact with and actuate its cooperating roll, andthus to vary the pitch of the propeller in one direction or the handlemay be operated to project the first ring and thus to vary the pitch ofthe propeller in the opposite direction.

Referringparticularly to Figs. 1 and 2 of the drawings, I have shown anaeroplane generally designated 11 having a cockpit 12 and a propeller 13driven by a motor 14. The blades 15 and 16 of the propeller 13 aremounted in a hub 17 which is secured to a shaft 18 so that'rotation ofthe shaft 18 by the motor 14 causes a rotation of the blades around theaxis of the shaft 18. The blades 15 and 16 are mounted in the hub insuch a manner that they may also be rotated around an axis longitudinalof the blades themselves This last mentioned rotation may beaccomplished by trains of gears including worm gears ,19 and 21 (seeFig. 2). Both trains of gears and both worms 19 and 21 may be driven bya single shaft 22 mounted to move with the propeller 13 in hearings onthe hub 17 and maintained substantially parallel to the longitudinalaxisof the blades of the propeller. This shaft 22 may be driven by eitherone'or the other of two friction rolls 23 and 24. As stated above, thefriction rolls 23 and 24 are adapted at times to contact with one or theother of a pair of friction rings. The outer ring of the pair is shownin Figs. 1 and 2 and is designated 25. Thru suitable connectionsincluding flexible shafts carried in conduits 26, 27 and 28, thefriction rings may be moved into and out of contact with the rolls 23and 24, each of the rings being automatically retracted out of contact,when the other ring is projected into contact. A handle 29 is providedwithin the cockpit of the aeroplane and is adapted to control theflexible shafts and the movement of the rings and thus through thefriction rolls 23 and 24, the trains of gears and the worms 19 and 21vary the pitch of the blades of the propeller.

. I will now describe in detail the mounting of the propeller blades andthe trains of gears by which rotation of the shaft 22 is at timeseffective to vary the pitch of the propeller blades. As shown in Fig. 5the hub 17 is formed in two halves 31 and 32. Each of these halves hasformed therein adjacent to each end a recess such as those shown at 34and 35. These recesses are adapted to receivea collar 36 which ismounted for rotation within said recesses. Washers such as 37 and 38 andball bearings such as 39 may be inserted between the collar 36 and thecasing of the hub 17. The inner part of the collar 36 is threaded toreceive the inner end of the propeller blade 15 and thus the propellerblade may rotate with the collar about an axis longitudinal of saidblade. The halves 31 and 32 may be secured together b split clamp bands40, 40, 41 and 41* (see ig. 4) and by clamp bolts such as 42, 43 and 44(Figs. 3 and'4) passing through the flanged ends of the clamps 40, 40 41and 41*. Pairs of brackets such as 45 and 46 and 47 and 48 (see Fig. 6)maybe mounted on each of the clamp bands 40* and 41 The pair of brackets47 and 48 may carry journaled in their upper ends a shaft 49 upon whichis mounted the worm gear 21 and the brackets 45 and 46 may carryjournaled in their upper ends a shaft 51 on which is mounted the wormgear 19.

Referring again to Figs. 4 and 5 it may be seen that the propeller blade15 has fastened around its periphery adjacent to the hub 17 a bracket 52clamped securely to said blade by means of the bolt 53. Likewise, theblade 16 has clamped thereto in a similar manner a bracket 54 securelyheld by the bolt 55. Bushings such as that shown at56 may be insertedbetween the butt of the pro- 18381161 blade and the associated clampring.

et-screws such as that shown at 57 may be inserted in each bracket tomaintain the desired relation betweenthe bracket and the propellerblade. The brackets 52 and 54 have inwardly extending arms 59 and 61,respectively, upon which are mounted sector gears 62 and 62 (see Figs. 5and 3) for meshing with the worm gears 19 and 21, respectively. Thus,rotation of the worm gears 19 and 21 is adapted to cause a rotation ofthe propeller blades 15 and 16 about their longitudinal axis, the bladesturning with their 'collars within the recesses in the hub 17. I I

,As stated above, I provide suitable gearing by-which the worms 19 and21 may be driven in synchronism from the shaft 22. As shown clearly inFig. 4, the end of the shaft brackets 68 and 69. The said brackets 68'and 69 may project upward from the propeller hub 17 and continuouslyrotate with the hub about the axis of the shaft 18. It may be noted thatthe gears are so arranged that rotation of the shaft 22 in either direction about its own axis will cause a rotation of the propeller blades 15and 16 about their longitudinal axis in directions the one op posite tothe other.

As is also shown most clearly in Fig. 4 I provide means responsive torotation of the friction rolls 23 and 24 for driving the shaft 22.Mounted upon the shaft 22 are two gear wheels 71 and 72 adapted to bedriven by the worm gears 73 and 74 and adapted to drive the shaft 22through the friction clutches 70 and 7 0 (later to be described indetail). The worm gears 73 and 74 are secured respectively to the endsof shafts 75 and 76 which are uppermost when the shafts are in thepositions shown in Fig. 4. The shaft 75 may be mounted in bearings in abracket 77 projecting rearward from the hub 17 and the shaft 76 may bemounted in bearings in a bracket 78 also projecting rearward from thehub 17. Secured to the lower endof the shaft 75 is a gear 81 adapted tobe driven by a worm gear 79 secured to one end of the shaft 82. Theshaft 82 may be mounted in a bearing 83 projecting rearward fromthepropeller hub 17 and may carry at its end opposite to the worm, gear79 the'friction roll 24. In a like manner the shaft 76 may have securedto its lower end a gear 85 adapted to be driven by a worm gear 84secured to one end of a shaft 86. The shaft 86 may be mounted in abearing 87 projecting rearward from the propeller hub 17 and may carryat its end opposite to the worm gear 85 the friction roll 23. It may beseen that rotation of the friction rolls 23 or 245 will cause rotationof the shaft 22 and a consequent variation iii the pitch of the bladesof the propeller. Rotation of the friction roll 23 will cause rotationof the shaft 22 in one direction while rotation of the roll-24 willcause rotation of the shaft 22 in the opposite direction. Because of theworm and gear wheel drive from the friction rolls to the shaft 22, thetransmission of motion isirreversible- "and rotation of the shaft 22 isineffective to cause an movement of the 'friction 'iolls 23 inserted thefriction clutches and 70" in the connections between the wheels 71 and72 respectively and the shaft 22. As shown more specifically in Fig. 7the wheel 72 is not keyed directly to the shaft 22. Surrounding theshaft 22 and splined thereto is a partially conical collar 84 which mayslide freely longitudinally of the shaft 22. Another partially conicalcollar 85 is telescoped over the collar 84 and may rotate around andslide longitudinally thereover. Screw threaded upon the smaller end ofthe collar 84 are nuts 86 and 87 and a spiral spring 88 is insertedwithin a recess between the collars 84 and 85 and is ada ted to bearupon the nut 86 and upon a shoul er formed within the collar 85 so thatit constantly urges the-collars 84 and 85 to move longitudinally of theshaft 22, as it were, toward each other. This movement tends to wedgethe collars within the gear 72 and thus to cause a friction drivebetween the gear 72 and the shaft 22. However, when the gear 72 islocked against movement by rea-, son of the immobility of the worm 74the clutch 70" is designed to slip and allow rotation of the shaft 22without movement of the gear 72. During the slipping of the clutch thecollar will be moved away from the collar 84 and will compress thespring 88. The structure and operation of the clutch 70 is similar tothe clutch 7 0. If desired, small toggle cams or dogs maybe introducedinto the; clutch combination to make the action positive when each geartrain picks up the driving motion. I The means for driving the frictionvrolls 23 and 24 is illustrated most clearly in Fig. 3, 6, 12 and 13.The rolls 23 and 24 are mounted for rotation concentrically about theaxis of the shaft 18, but are not equidistant from said axis. As shownin Fig. 6 the roll 24 registers substantially with the friction ring 25but the roll 23 is arranged to travel in a path within the friction ring25. A friction ring rings 25 and 89 to move them into an out 0f contactwith the rolls 23 and 24. Within .the guide 91 a rack 93 is secured tothe ring 25 and a rack 94 is secured to the ring 89. 7 Similarly in theguide 92 a rack 95 is secured to the ring 25 and a rack 96 is secured tothe Means are provided for reciprocatin the ring 89. Extending throughthe guide casings. 91 and 92, respectively, are-shafts 97 and 98 theformer of which carries a pinion 99 meshing with the racks 93 and' 94and the latter of which carries a pinion 101 meshing with the'racks 95and 96. It is thus clear that by suitable rotation of the shafts 97 and98, the friction rings 25 and 89 may be projected to contact with theircooperating rolls or may be retracted to move out of contact with therolls. Thus, the ring 25.

' may at times serve as a track for the roll 24 and the ring 89 may atother times serve as a track for the 'roll 23. Inasmuch as the propeller 13 is being continuously rotated by the shaft 18 it is clear thatwhen one or the other of the tracks or 89 has been projected intocont'act'with its associated roll, the movement of the roll around theaxis of the shaft 18 will cause a rotation of the associated shafts 82or 86 and a consequent rotation-of the shaft 22. By reason of thedirection of the worm drives, it is also clear that when the roll 23 isin contact with its friction ring 89 the shaft 22 is driven'inadirection opposite to that in which it is driven when the roll-24 is incontact with its friction ring 25.

As shown in Figs. 8 and 9, I, provide meansfor cushioning the drivethrough the various gears so that a too sudden starting or stopping ofthe gears will not cause breakage of parts Inasmuch as this device isthe same for both of the rolls 23 and 2.4, description of one willsuflfice. The friction roll 23 comprises an outer ring 102 having inwardprojections 103, 104 and 105 and. an inner ring 106 having outwardpfojections 107, 108 and 109. A groove 110 is provided between the outerring 102 and the inner ring106 'and. inserted in this groove between theprojections 103, 104, 105, 107, 108 and 109 are compression springs suchas the spring 111. Thus movement of the outer ring 102 causes acushioned movement of the inner ring 106 and consequent rotation of theshaft 22.

One means for distributing the movement ofthe flexibleshaft connectionleading from the.cockpit.is shown clearly in Fig. 11. The

, flexible shaft connection from the cockpitis adapted to turn a shaft IV 107 and through it the bevel wheel 108. The bevel wheel 108 mesheswith the twq bevel wheels 109 and 111 and thus is adapted 'to drive theshafts 112 and 113. .The shaft 112 is connected to a suitable flexibleshaft leading through the conduits 27 and the shaft 113 is connected toa flexible shaft leading through the conduit 28. i

As shown in Fig. 1.0, a spring 114 may be connected to the handle 29 inorder to maintain it in either of its operative positions and thus tohold the rings 25 or 89 firmly in contact with therolls 23 and 24.

The operation of my improved variable pitch propeller will be apparentfrom the above'description. The pilot by movement of the control handle29 moves the ring 25 or the" ring 89 into contact with one or the otherof .he rolls 23 and 24 and by reason of the rotation of the rolls 23andv 24 around the shaft 18 causes rotation of the shaft 22 in thedesired direction. This rotation of the shaft 22 is transmitted throughthe gearing to the sector gears 62 and 62 and causes rotation of thepropeller blades 15 and 16 about their longitudinal axis 'to vary theinclination of the blades with respect to the thrust of the propeller.

I have shown in Figs. 14 and 15 a slightly modified form of apparatusconstructed according to my invention, and have used the same numeralsto indicate corresponding parts. A shaft 86 carries on one end a worm 84and on its opposite end a roll 23. A shaft 82 carries on one end a 'worm7 9 similar to the worm 79 but having the spirals thereof reversed ascompared With the spirals of the worm 79. The shaft 82 carries at itsopposite end a roll 24. The two rings 25 and 89 are replaced by a singledouble flanged ring 25 The ring 25 is constructed so as to have twoparallel flanges 25 and 25 embracing the rolls 23 and 24. Racks 94 and96' are attached to the ring 25 in order that the ring may be movedtoward and away from the hub of the propeller'to bring the flange 25 orthe flange 25 into contact with the rolls 23 and 24. Pinions .99 andlOlare arranged to be actuated in a manner similar to that describedabovein order to move the racks 94 and 96, respectively. I

The operation of this'form of my invention is quite similar to theoperation of the previously described form. The pilot, by

operation of the handle 29, is able to rotate the pinions 99 and 101 andthus to move the flange 25 or the flange 25 into contact with the roll23 or 24. If the flange 25 is moved into contact with the rolls it willcause a rotation of the shaft 22 in one direction while if the flan'ge25 is moved into contact with the rolls-it will cause opposite rotationof the shafts 82 and 86 and a consequent'opposite rotation of the shaft22. The rotation of the shaft 22 will, as previously described, cause avariation in the pitch of the blades of the propeller, the direction andamount of the variation being under the control of the pilot by thehandle in the cockpit. In the use for instance 24, and its associatedparts including'the shaft 82, the worm-79 the bearing'83, the worm wheel81, the bracket 77,

the shaft 75, the worm 73 and the worm wheel 71 may also'be omitted.

A two bladed tractor propeller is shown in the drawings. I do not desireto limit myself-to such specific types, but if such a course should bedeemed advisable, may use a two bladed pusher propeller or a pusher ortractor propeller having mof'e' than two blades. Any unbalance caused bythe mechanism on the propeller may be compensated for by suitablecounterweights fixed to the propeller hub.

I have illustrated my invention as aproeller for driving an airplane inhorizontal 'ght. Propeller blades or air screws made up of win surfacesmay also be used for lifting aerial vehicles vertically or substantiallyvertically as in such devices as helicopters. I may apply myinvention'thereto and in the'a pended claims I desire the word drive tobe construed as meaning either driving in a horizontal direction or in avertical direction or in any combination thereof. 1 It is to beunderstood that the above described embodiments of my invention are forthe purpose of illustration only and various changes may be made thereinwithout departing rom the spirit and scope of my invention. a

I claim as my invention: 1. In anaerial vehicle; a propeller; means forrotating the propeller to cause it to drive the aerial vehicle; andmeans for varying thepitch of the propeller while it is rotating, saidlast named means comprising a frictlon dr ve wheel, a train of gearsdriven by sald drive wheel, and a friction clutch ineluded insaid train.

' 2. In an aerial vehicle; a ropeller having a hub and blades; means orrotating the propeller to cause it to drive the aerial ,vehi-.

ole; means forchanging the angle of inclination of all of the blades ofthe propeller comprising a plurality of similar gear trains mountedonthe hub of said propeller and each connected to one of the propellerblades;

3. In an aerial vehicle; a propeller having a hub and blades ;means' forrotatin the ro-, peller to cause it to drive the aeria vehicle; andmeans for varying'the angle of inclination of each of the blades of saidpropeller,

said last named means comprising a pluralit of similar ear trainsmounted on the hub 0 said propel er, each train being connected to oneof the pro eller blades, a sin le shaft mounted on the ub for driving alof the gear trains, duplicate drive shafts, each of which separately isadapted to drive the single shaft friction drive wheels also mount ed onsald hub, and agear connection 'between the friction drive wheels andthe last named drive shafts.

" I. In an aerial vehicle; a propeller having a hub and blades; meansfor rotating the propeller to cause it to drive the aerial-ve;

hicle; and means for varying the angle f inclination of all of theblades of said propeller, said last named means comprising a pluralityof gear trains, each of said gear trains being connectedto one of saidprofriction drive wheels each connected to one of the last named trainof gears.

5. In an aerial vehicle; a propeller having a hub and blades; means forrotating the propeller to cause it to drive the aerial vehicle; andmeans for varying the angle of inclination of all of the blades of saidpropeller, said last named means comprising a. plurality ofgear trainseach of which gear trains is connected to one of said propeller blades,a single shaft also mounted on the hub for driving both of the said geartrains, a plurality of drive shafts for separately driving the saidsingle shaft, a train of gears connected to each of said drive shafts, aplu rality of friction drive wheels each connected to one of the lastnamed train of gears, the said friction wheels being arranged to travel,in concentric paths, but each friction wheel being positioned at adifferent distance from the common center of said paths.

6. In an aerial vehicle; a

propeller having a hub and blades; means or rotating the propeller tocause it to drive the aerial vehicle; and means for varying the angle ofinclination of all of the blades of said propeller comprising aplurality of gear trains, each of which gear trains is connected to oneof said propeller blades, a single shaft also mounted on the hub fordriving all of the said gear trains, a plurality of similar drive shaftsfor separately driving said sin le shaft, trains of-gea'rs connected tosaid drive shafts, friction drive wheels eachconnected to one of thelast named train of gears, and

concentric friction rings upon which the fric- 1 tion wheels may bear.7. In an aerial vehicle; a propeller having .a hub and blades; means forrotating the propeller to cause it to drive the aerial vehicle; andmeans for varying the an 1e of inclination of all of the blades of saipropeller comprising a plurality of gear trams mounted on the hub of thepropeller, each of said gear trains being connected to one of saidpropeller blades, a, single shaft also mounted on the hub for drivingall of sald gear trains, a plurality of drive shafts for separatelydriving said single shaft, tgears connected to said duplicate drive shats, a pair of friction. drive Wheels each connected to one of the lastnamed train of gears, and non-rotating concentric friction rings uponwhich the friction wheels may bear.

8. In an'aerial vehicle; a propeller having a hub and blades, means forrotating the propeller to cause it to drive the aerial vea compressionhide; and means for varying the inclination of said blades of thepropeller comprising racks secured to the blades, a shaft positioneadjacent to said racks, worm gears upon said shaft meshing with saidracks, a worm wheel also upon said shaft, a second shaft arrangedsubstantially parallel to the longitudinal axis of the propeller blade,a worm gear upon said parallel shaft meshing with said worm wheel, andmeans including a friction wheel -for driving said parallel shaft.

9. In an aerial vehicle; a propeller having a hub and blades; means forrotatin the propeller .to cause it to drive the aerial vehicle; andmeans for varying the angle of "inclination of said blades of thepropeller comprising a gear train mounted on the hub of the propeller; afriction drive wheel for driving said gear train; and means interposed1n said gear train for cushioning the drive through the various gears,said last named means comprisin an outer ring formed with internal proections, an inner ring formed with external projections and springsinserted between said projections.

10. In an aerial vehicle; a propeller hav- 7 ing a hub and .blade's;means for rotating the propeller to cause it -to drive: the aerialvehicle; and means for varying the angle of inclination of all of the.blades of the pro.- peller comprising a plurality of similar ear trainsmounted onthe hub ofthe prope er, each train beingconnected to one bladeof the propeller, a single shaft also mounted on the hub of thepropeller and connected to said gear trains for drivin said trains, andmeans for drivin said sing e shaft including a pair of drive-Ls'aftsiadapted-to se arately and selectiveiy" drive said single sha inop- 1 p'osite directions. v 3 Y 11, Br an airplane,'a'propellercomprising a hub, blades extending radially from-and adapted to turnwith respect to said" hub 'about their axes, racks "on said .blades', aplurality of bearing brackets mounted on said hub,=worms revoluble inpart of said brackets, and engaging said racks, a sin leshaft revolublein ,others "of said brac ets and adapted to simultaneously turn saidworms, 1

a plurality of operably connected gear reductions terminatin meansifor's'aid-singfia shaft'and terminatin at the other end in a friction wheeladapte to turn said gear reductions, torque cushioning means interposedin said plurality of gear reductions, a track mountedon said airplaneand adapted to engagesaid friction wheel, and control means tooptionally'engage said track with said friction wheel.

In testimony whereof I hereunto aflix'my signature. v EDMUND B. MOORE.

at one end in driving

